Stair square



c. A. cHRls'rlANsoN STAIR SQUARE Filed May 26, 1925 Patented pr. l2,11927.

UNITED STATES PATENT OFFICE.

STAIR SQUARE.

Application filed May 26, 1925. Serial No. Y33,073.

The present invention relates to a stair square which may be used toobtain the length, treads, and rises between the walls and stairstringers, and in building circu- '5 lar stairs, it may be used as abevel square at both ends. rThe device is t'urther useful in obtainingthe length and niiter cut .of balusters between the top and bottonirails.

In the drawing,

Figure 1 is an elevation of the device extended,

Figure 2 is an elevation of the device folded,

Figures 3 and 4 are sections taken on the lines 8-3 and 4-1 respectivelyof F ig. 2,

Fig. 5 is a section through the hinged joint.

Referring to the drawings in ldetail, it

will be seen that the numerals and 5 denote a pair ot' bars,hingedtogether as at b' so that they may be swung to the positions shownin Figs. 1 and 2. The hinged joint 6 is constructed to limit theswinging orn one bar-with respect to the other in van arc of 180". Thebars 5 and have longitudinally extending slots 7 and 7 respectively t'orreceiving bolts 8 and 8 on which are threaded thulnb nuts 9 and 9. Bars10 and 10 are pierced at Vone end by the bolts 8 and 8 respectively andhave Inortises to slidably receive bars 5 and 5 respectively. Plates 11and 11 are pierced by the bolts 8 and 8 respectively and eX- tend overthe bars 5 and 5 respectively and 35 bars 1()y and 10 respectively.Blades 12 and 12 are formed at one end with slots 14 and 14respectively. The slotted ends ot' the blades 12 and 12 extend betweenthe plates 11 and 11 respectively and the bars 40 10 and 10 respectivelyand the bolts 15 Y and 15 pierce openings in the plates 11 and 11respectively, and the bars 10 and 10 respectively and also the slots 11and 11 respectively. Thumb nuts 16 and 16 are 45 threaded on the bolts15 and 15 respectively. The `free extremities ot the blades are beveled.y

Having thus described niy invention, what I clailn as new is:

A device of the class describedincluding a pair of hinged bars, a secondpair otl bars slidable on the first pair of bars, means limiting thesliding ot' the bars in relation to one another and operable to hold thebars in different adjusted positions, plates on the second bars andextending over the iirst bars, a pair ot' blades, and adjustable pin andslot connections-between the blades and the second bars and the plates.

CHRIST A.v CHRISTIANSON.

